Core E is the Biostatistics core. It will serve as a resource for the four projects, and interact with other cores, providing statistical support. The main functions of the core are: (1) to assist in the design of experiments, calculation of sample size and power, (2) to assist in the choice of appropriate computer data entry and statistical software, (3) to provide assistance and advice in statistical data analysis, and (4) to provide internal statistical review of publications before they are submitted.